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Ziel der vorliegenden Untersuchung war es, Aufschluß über die unterschiedliche Qualität hierarchischer und nicht-hierarchischer (partionierender) Clusteranalyseverfahren zu gewinnen. Die Reproduktionsgüte beider Clusteranalyse-Varianten wurde anhand von 200 Monte-Carlo-Datensätzen (multivariat normalverteilte Mixturen) zu überprüfen versucht, wobei jeweils unterschiedliche Proportionen der Daten-Elemente klassifiZiert werden mußten. Es zeigte sich, daß insgesamt gesehen die hierarchischen Algorithmen nach WARD und LANCE-WILUAMS am besten dazu in der Lage waren, die vorgegebenen Datenstrukturen zu reproduzieren, andererseits aber die herangezogenen partitionierenden KMEANS-Verfahren nicht schlechter abschnitten, wenn die Lösung der WARD-Technik als Start-Partition vorgegeben wurde.
Es wird ein Oberblick über Evaluationsstudien gegeben, die sich mit der Validität von Clusteranalyse-Algorithmen befassen. Im Anschluß an die Diskussion möglicher Bewertungskriterien werden Vergleichsuntersuchungen näher analysiert und danach geordnet, ob sie empirische Datensätze, Plasmaden oder Monte-Carlo-Datensätze als Evaluationsgrundlage benutzen. Die Obersicht über komplexer angelegte Monte-Carlo-Studien zeigt die unterschiedliche Qualität der verfügbaren Clusteranalyse-Algorithmen auf, macht andererseits aber auch deutlich, daß bestimmte hierarchisch-agglomerative Verfahren wie etwa die Methoden nachWARD oder LANCE-WILLIAMS bzw. iterativpartitionierende Prozeduren wie etwa die KMEANS-Algorithmen als relativ robuste Klassifikationsverfahren gelten können.
Objective
Most patients with bipolar disorders (BD) exhibit prodromal symptoms before a first (hypo)manic episode. Patients with clinically significant symptoms fulfilling at‐risk criteria for serious mental illness (SMI) require effective and safe treatment. Cognitive‐behavioral psychotherapy (CBT) has shown promising results in early stages of BD and in patients at high risk for psychosis. We aimed to investigate whether group CBT can improve symptoms and functional deficits in young patients at risk for SMI presenting with subthreshold bipolar symptoms.
Method
In a multicenter, randomized, controlled trial, patients at clinical risk for SMI presenting with subthreshold bipolar symptoms aged 15‐30 years were randomized to 14 weeks of at‐risk for BD‐specific group CBT or unstructured group meetings. Primary efficacy endpoints were differences in affective symptomatology and psychosocial functioning at 14 weeks. At‐risk status was defined as a combination of subthreshold bipolar symptomatology, reduction of psychosocial functioning and a family history for (schizo)affective disorders. A prespecified interim analysis was conducted at 75% of the targeted sample.
Results
Of 128 screened participants, 75 were randomized to group CBT (n = 38, completers = 65.8%) vs unstructured group meetings (n = 37, completers = 78.4%). Affective symptomatology and psychosocial functioning improved significantly at week 14 (P < .001) and during 6 months (P < .001) in both groups, without significant between‐group differences. Findings are limited by the interim character of the analysis, the use of not fully validated early detection interviews, a newly adapted intervention manual, and the substantial drop‐outs.
Conclusions
Results suggest that young patients at‐risk for SMI presenting with subthreshold bipolar symptoms benefit from early group sessions. The degree of specificity and psychotherapeutic interaction needed requires clarification.
Risk prediction in patients with heart failure (HF) is essential to improve the tailoring of preventive, diagnostic, and therapeutic strategies for the individual patient, and effectively use health care resources. Risk scores derived from controlled clinical studies can be used to calculate the risk of mortality and HF hospitalizations. However, these scores are poorly implemented into routine care, predominantly because their calculation requires considerable efforts in practice and necessary data often are not available in an interoperable format. In this work, we demonstrate the feasibility of a multi-site solution to derive and calculate two exemplary HF scores from clinical routine data (MAGGIC score with six continuous and eight categorical variables; Barcelona Bio-HF score with five continuous and six categorical variables). Within HiGHmed, a German Medical Informatics Initiative consortium, we implemented an interoperable solution, collecting a harmonized HF-phenotypic core data set (CDS) within the openEHR framework. Our approach minimizes the need for manual data entry by automatically retrieving data from primary systems. We show, across five participating medical centers, that the implemented structures to execute dedicated data queries, followed by harmonized data processing and score calculation, work well in practice. In summary, we demonstrated the feasibility of clinical routine data usage across multiple partner sites to compute HF risk scores. This solution can be extended to a large spectrum of applications in clinical care.
Background
The intent of this pooled analysis as part of the German society for radiation oncology (DEGRO) stereotactic body radiotherapy (SBRT) initiative was to analyze the patterns of care of SBRT for liver oligometastases and to derive factors influencing treated metastases control and overall survival in a large patient cohort.
Methods
From 17 German and Swiss centers, data on all patients treated for liver oligometastases with SBRT since its introduction in 1997 has been collected and entered into a centralized database. In addition to patient and tumor characteristics, data on immobilization, image guidance and motion management as well as dose prescription and fractionation has been gathered. Besides dose response and survival statistics, time trends of the aforementioned variables have been investigated.
Results
In total, 474 patients with 623 liver oligometastases (median 1 lesion/patient; range 1–4) have been collected from 1997 until 2015. Predominant histologies were colorectal cancer (n = 213 pts.; 300 lesions) and breast cancer (n = 57; 81 lesions). All centers employed an SBRT specific setup. Initially, stereotactic coordinates and CT simulation were used for treatment set-up (55%), but eventually were replaced by CBCT guidance (28%) or more recently robotic tracking (17%). High variance in fraction (fx) number (median 1 fx; range 1–13) and dose per fraction (median: 18.5 Gy; range 3–37.5 Gy) was observed, although median BED remained consistently high after an initial learning curve. Median follow-up time was 15 months; median overall survival after SBRT was 24 months. One- and 2-year treated metastases control rate of treated lesions was 77% and 64%; if maximum isocenter biological equivalent dose (BED) was greater than 150 Gy EQD2Gy, it increased to 83% and 70%, respectively. Besides radiation dose colorectal and breast histology and motion management methods were associated with improved treated metastases control.
Conclusion
After an initial learning curve with regards to total cumulative doses, consistently high biologically effective doses have been employed translating into high local tumor control at 1 and 2 years. The true impact of histology and motion management method on treated metastases control deserve deeper analysis. Overall survival is mainly influenced by histology and metastatic tumor burden.